Resinous composition and process of making the same.



STATES PATENT OFFICE.

MTCHAEL J. CALLAHAN. OF PITTSFIELD. MASSACHUSETTS,. ASSIGNOR T0 GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

RESINOUS COMPOSITION AND PROCESS OF MAKING THE SAME.

mos; as.

No Drawing.

lle it known that I, MiciL-uu. .T. GALLA- ii.\: a citizen of the UnitedStates, residing: at littslicld. county of Berkshire, State ot'idlissmchusetts, have invented certain new and useful Improvements inResinous Compositions and the Process of Making the Same, of which thefollowing is a specification.

This application is in part a continuation of my prior application,Serial No. 094,250, filed May 1, 1912.

The present invention relates to synthetic resinous, gummy or plasticcompositions usually known as condensation Products and suitable for,various purposes in the arts such as electrical insulations, moldedmaterials, varnishes, and the like.

liesinous materials for certain technical uses. particularly forelectrical insulation, should be strong and possess some degree offlexibility and tenacity. Many synthetic resins are more or less brittleand are for this reason greatly handicapped for many industrialpurposes.

My present invention comprises an exceedingly strong, tough and flexibleresinous product made by the interaction of a polyhydric alcohol, suchas "glycerin and a mix ture of a. polybasic acid of the aromatic seriesor its anhydrid, for example, phthalic anhydrid, and a dibasic acid ofthe aliphatic series, particularly ,succinic acid.

In carrying out my invention a desired mixture of the acids is mixedWith a m0lecular equivalent proportion of a polyhydric alcohol and areaction is caused by heating. For example, about 118.4 parts by Weightof phthalic anhydrid, Which corresponds to four-fifths of a molecularpart, about 141.5 parts by weight of'succinic acid which corresponds toone and one fifth molecular parts, and about 1841 parts by weight of100% glycerin which corresponds to two molecular parts, are mixed in asuitable retort and heated. The exact molecular proportions need not bestrictly adhered to, an excess of glycerin for example will be drivenoil during the latter part of the reaction. The reaction takes place intwo stages; first, the formation of a fusible, soluble product, andsecondly, the transformation of this product to an infusible, in-

Specification of Letters Patent.

Application filed July 9.1913.

Patented All". 25, 1914.

Serial No. 778,116.

soluble state. The completion of the first reaction can be ascertainedby taking out a small sample and allowing; it to cool. If the cooledproduct is viscous but not sticky, the reaction has gone far enough. Atthis stage the product is soluble in acetone, making a clear solutionuset'ul as a. varnish. It is also soluble in colophony, and glycerin.

If desired, the second reaction may be caused to take place and theproduct rendered infusible and substantially insoluble in commonsolvents, such as acetone, by heating' to a moderate temperature, sayabout 85 C. to 150 (l. for a considerable length of time. The length ofheating will vary with the temperature used and the composition of thematerial. I have found that in many cases heating: to a temperature of85* (I. at atmospheric pressure for about fifteen hours is suflicient toaccomplish the final reaction. By raising the temperature this length oftime may be reduced. example, a layer one-tenth of an inch inthickness-will harden in ten hours at 150 C. When the final hardeningtemperature is too high, a rapid evolution of vapor results, causing theproduct to be filled with cavities. When overheating is avoided a verystrong, homogeneous, transparent resin is produced which has a highinsulating value and is relatively inert chemically. The infusible resinmay be dissolved in about an equal part of glycerin.

The amounts of the two classes of polybasic acids may be varied tocorrespond with the properties desired in the finished resin. Forexample a greater amount of succinic acid may be used withacorrespondingly smaller amount of phthalic anhydrid to make a softerand more flexible product.

Instead of using the particular compounds given as examples, theirhomologues may in some cases be used. For example, sebacic acid may beused in place of succinic acid.

Chemically the resinous products thus obtained may be mixtures of estersof glycerin, or the like, and the respective acids. However, thediliiculty accompanying the investigation of resinous bodies is Wellknown. It may be that a very complex molecular structure is involved.Both the fusible and infusible resin may be saponified with a dilutealkali such as sodium hydroxid to re generate glycerine, or other polrhvdric alcohol, and form the corresponding sodium salt of the organicacids used, for example, the phthalate and the succinate of sodium.

By inipregating fibrous, or cellular material with the acetone solutionof the material in its soluble stage, the material may be introducedinto the interstices of a body and then rendered insoluble andinfusible. If desired the fusible resin may be mixed with about 10 to ofnaphthalene and the fused mixture used under pressure as an impregnatingcompound for electrical coils and the like as described in my copendinqapplication Serial No. 747,115, filed heb. S, 1913, the naphthalenebeing subsequently driven off, and the resin hardened by heating.

hat I claim as new and desire to secure by Letters Patent of the UnitedStates, is,'-

l. The herein described tough, flexible material, being a mixture ofesters formed by the interaction of a polyhydric alcohol, a dibasic acidof the aliphatic series and a sessing highelectrical insulatingproperties,

a correspoi'iding alkali salt of the acids employed.

2. ..\s a ((flinpUEsl LlOH of matter, a tough, flexible resinousmaterial, being a mixture of glyceryl esters formed by the interactionof glycerin, succinic acid and phthalic anhydrid. iiiiusible withoutdecomposition, insoluble in common organic solvents, being saponifiablewith dilute alkali to regenerate glycerin and form the succinate and thephlhalate of the alkali.

As a composition of matter, a tough, flexible resin, being a mixture ofgglyceryl esters formed by the interaction of about 1 parts otgl 'cerin,about 1-1-1 parts of SHCCllllC acid and about 118 parts of phthalieanhydrid by weight, having high insulating properties infusible withoutdecomposition,

substantially insoluble in common solvents, being sapo-nifiable withdilute alkali to regenerate glycerin and form the succiiiate and thephthalate oi the alkali.

In witness whereot, I have hereunto set my hand this 2nd day of July,1913. POkYlJtISlC acid of thenromatic series, insoluble and infusiblewithout decomposition, posand being saponifiable With dilute alkali to 1regenerate the polyhydric alcohol and form l MICHAEL J. CALLAHAN.

\Vitnesses:

Toxi' Biiiaoxe, JL'LIAN S. GnAviiiir.

